2004 CORN ROOTWORM SOIL
INSECTICIDE EVALUATION1
University of Nebraska
Agricultural Research and Development Center
Mead, Nebraska
Lance J. Meinke, Jim Brown,
Laura Campbell, Bill McCormick
Department of Entomology
University of Nebraska
Lincoln, Nebraska 68583-0816
Background information pertaining to the experiment conducted at the ARDC, near Mead, Nebraska during 2004.
| Background Information - Agronomic | Background Information - Entomology |
| Experimental Design | Environmental Conditions at Planting |
| Rainfall and Irrigation | Root Damage Evaluations |
Hybrid: DKC 60-15
Row Spacing: 30 inches
Planting Date: 28 April 2004
Planter: Kinze model 2100, 4 row cone
Planting Depth: 2 inches
Application Equipment: Granular insecticides
Planting: planter mounted cone-belt system or Smartbox system
Liquid insecticides
Planter mounted CO2 pressurized sprayer
Field Preparation: 20 April 2004 - disked
Herbicides Applied: 29 April 2004: Harness Xtra, 2.5 qt/A, pre emerge
10 June 2004: 1.0 oz Permit + 0.67 oz Accent / A
Fertilizer Applied: 150 lb. N/A applied as NH3, 15 April 2004
Previous Crop: Continuous corn (trap crop)
Soil Information:
Type: Silty clay loam
Ph: 6.4
CEC: 29.4
% organic matter: 2.8
% clay: 29.05
% silt: 66.67
% sand: 4.28
Plant Population: There were no significant differences (P > 0.05) among treatment
stand count means or among abnormal plants per treatment at V3
growth stage (Hanway 1997). The overall mean number of plants/33.5' + SEM = 44.84 + 0.38.
Insecticide History: Insecticide free: 1997, 1999, 2001, 2003
Multiclass soil insecticide trials: 1996, 1998, 2000, 2002
Species present: Northern corn rootworm, Diabrotica barberi Smith and Lawrence, and western corn rootworm, D. virgifera virgifera LeConte. Initial rootworm egg hatch occurred between 22-23 May 2004 (predominantly western corn rootworm).
Root Evaluation: 1-6 (Hills and Peters 1971) and 0-3 root rating scales (J. Oleson, Iowa State University) were used to evaluate larval corn rootworm damage in each treatment. Five roots per replication were evaluated in each treatment.
Root Evaluation Date: 14 July 2004
Design: Randomized complete block design
Replicated four times
Single row treatments
Row Length: 33.5 feet
Statistical Analysis: Stand Counts, Root Ratings: Used SAS Mixed Procedure; Protected LSD test was used for mean separation (P ≤ 0.05) .
Conditions at planting:
Air temperature: 27°C
Wind speed: 20 mph at 5 ft height
Wind direction: SW
Soil temperature 2" depth: 18°C
Soil temperature surface: 24°C
Soil moisture, 0-3" depth: 13.5 % water (gravimetric method)
% cloud cover: 10 % cloud cover
% relative humidity: not recorded
Residue on surface: 20% of soil surface covered with crop residue; soil moist, mellow, good seed bed
April 09 0.039 inch
18 0.039
20 0.039
24 0.787
Total 0.904
May 01 0.039 inch
10 0.512
12 0.039
13 0.079
14 0.039
15 0.039
16 0.039
17 0.039
18 0.118
22 1.890
24 0.236
26 0.157
29 1.063
Total 4.289
June 05 0.236 inch
12 2.323
13 0.079
15 0.118
18 0.236
21 0.236
24 0.039
Total 3.267
July 02 0.906 inch
03 0.236
05 0.157
06 0.079
07 0.354
08 0.039
11 0.118
14 0.236
22 0.039
23 0.039
24 0.039
29 0.039
30 0.039
Total 2.320
Irrigation (through July 2004):
Sprinkler irrigation was applied periodically between planting and root damage evaluation.
July 02 1.0 inch
20 1.0
21 1.0
30 1.5
Table 1. 2004 Corn Rootworm Soil Insecticide Experiment 1.
University of Nebraska Agricultural Research and Development Center, near Mead, NE
Root Damage Evaluation
| Insecticide | Rate/Placementa | Mean Percentageb Lodged (+ SE) | Mean Root Damage Ratingc (1 - 6 Scale) | Mean Root Damage Ratingc (0 - 3 Scale) |
|---|---|---|---|---|
| YieldGard Rootwormd + Poncho 250 | 0.00 + 0.00 | 1.95 a | 0.05 a | |
| Aztec 2.1 + Poncho 1250 | 0.07 TB | 0.72 + 0.72 | 2.30 ab | 0.15 ab |
| Aztec 3.78G | 0.137 TB | 1.22 + 1.22 | 2.45 abc | 0.17 abc |
| Counter 15G | 1.2 TB | 0.66 + 0.66 | 2.50 abcd | 0.12 ab |
| Regent 4 SC | see footnote e | 0.00 + 0.00 | 2.55 abcd | 0.18 abc |
| Fortress 2.5G | 0.20 I | 2.33 + 1.61 | 2.55 abcd | 0.23 abc |
| Aztec 2.1G | 0.141 TB | 2.53 + 1.81 | 2.60 bcde | 0.29 abc |
| Force 3G | 0.12 TB | 1.97 + 1.26 | 2.75 bcdef | 0.24 abc |
| Aztec 4.67G | 0.14 TB smartbox appl. | 5.37 + 3.13 | 2.95 cdef | 0.36 abc |
| Lorsban 4E | see footnote f | 1.80 + 1.12 | 3.10 defg | 0.51 abcd |
| Force 3G | 0.12 TB smartbox appl. | 7.64 + 4.07 | 3.10 defg | 0.52 abcd |
| Lorsban 15G | 1.2 TB | 3.75 + 3.75 | 3.10 defg | 0.52 abcd |
| Poncho 1250 | 1.25 mg ai/seed | 0.70 + 0.70 | 3.20 efgh | 0.57 bcd |
| Capture 2EC | see footnote g | 2.58 + 1.86 | 3.25 fghi | 0.67 cd |
| Cruiser 5 FS | 1.25 mg ai/seed | 14.75 + 5.98 | 3.70 ghi | 1.01 de |
| Capture 2EC | see footnote h | 12.63 + 10.33 | 3.75 hij | 1.18 e |
| Thimet 20G | 1.2 TB | 38.73 + 20.80 | 3.85 ij | 1.24 e |
| Fipronil ST | 50 g ai/100 kg seed | 40.22 + 16.97 | 4.35 j | 1.75 f |
| Untreated (1) | ------ | 57.84 + 17.37 | 5.00 k | 2.34 g |
| Untreated (2) | ------ | 70.17 + 11.36 | 5.10 k | 2.32 g |
a Rate presented as oz ai per 1000 row ft except where other units listed:
TB = T-band, 7-inch band placed over the open seed furrow;
I = placed in the open seed furrow;
ST = seed treatment.
b On 30 August 2004, there were no significant differences (P > 0.05) in final stand count means; the final overall mean number of plants per 33.5 ft + SEM = 39.99 + 0.38. The mean percentage of final stands that were lodged are presented by treatment (lodged = plant leaning > 45° angle from vertical).
c Root rating scales used: 1 - 6 scale (Hills and Peters 1971); 0 - 3 scale (J. Oleson, Iowa State
University); within columns, mean root rating values followed by the same letter are not
significantly different from each other (Fisher’s protected LSD test @ 0.05 significance level).
d YieldGard Rootworm: hybrid expresses Cry3Bb1 Bt-toxin.
e Regent 4SC rate: 0.13 lb ai/A; volume: 5 gallons water/A through microtube into open seed furrow
f Lorsban 4E rate: 1.2 oz ai/1000 ft; volume: 5 gallons water/A, TB application
g Capture 2EC rate: 0.09 oz ai/1000 ft; volume: 5 gallons water/A, TB application
h Capture 2EC: rate: 0.09 oz ai/1000 ft, volume: 5 gallons 10/34/0 starter fertilizer/A, microtube infurrow application